Mud volcano fields around Mt. Etna

Abstract

We have studied four mud volcano fields located in eastern Sicily, around the Mt. Etna edifice. Three of them are located on the southern flank of Etna, between the Paternò and Belpasso villages and, based of their location, are named “Salinelle dei Cappuccini”, “Salinelle del Fiume” and “Salinelle del Vallone Salato”. Their genesis is connected with a structural trap formed by a brachyanticline of Pleistocene clays that form the Etna basement. The fourth one is located on the farest north-eastern part of Etna, along the Ionian coastline, and it is named “Salsa di Fondachello” after the name of the closest village. Geologic surveys and drilling data allow us to say that in “Salinelle dei Cappuccini” and “Salinelle del Fiume” fluids uprise through pre-existing volcanic necks, while in “Salinelle del Vallone Salato” fluids presumably uprise through a fault plane. The morphological evolution of these mud volcano fields depends mainly on the density of the emitted muds and secondarily on preexisting features of the ground surface. Chemical analyses revealed that the water coming out from the mud volcanoes is a fossil marine water hosted in the Miocene sedimentary rocks of the Mt. Etna basement. CO2 is the most abundant escaping gas, and it is mainly of magmatic origin: its amount and rate could be related to movements of the deep Etna magma. The activity of the “Salsa di Fondachello” mud volcano started on January 11th, 1693, associated with the destructive Val di Noto earthquake. The mud volcano was again active from 1795 to 1832. At the end of its last activity, started in March 1847, an earthquake occurred and the mud volcano collapsed. Today only a weak methane emission is evidence of endogenous activity.